threading.h

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/*
 * Copyright (c) 2010-2011:  Steinbeis Forschungszentrum (STZ Ölbronn)
 * Author: Michael Hoffer
 * 
 * This file is part of UG4.
 * 
 * UG4 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 3 (as published by the
 * Free Software Foundation) with the following additional attribution
 * requirements (according to LGPL/GPL v3 §7):
 * 
 * (1) The following notice must be displayed in the Appropriate Legal Notices
 * of covered and combined works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (2) The following notice must be displayed at a prominent place in the
 * terminal output of covered works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (3) The following bibliography is recommended for citation and must be
 * preserved in all covered files:
 * "Reiter, S., Vogel, A., Heppner, I., Rupp, M., and Wittum, G. A massively
 *   parallel geometric multigrid solver on hierarchically distributed grids.
 *   Computing and visualization in science 16, 4 (2013), 151-164"
 * "Vogel, A., Reiter, S., Rupp, M., Nägel, A., and Wittum, G. UG4 -- a novel
 *   flexible software system for simulating pde based models on high performance
 *   computers. Computing and visualization in science 16, 4 (2013), 165-179"
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 */
 
#include <jni.h>
#include <stddef.h>
#include "messaging.h"
#include "bindings_vrl.h"
 
#ifndef THREADING_H
#define THREADING_H
namespace ug {
  namespace vrl {
    namespace threading {
 
      enum ExceptionType {
        ATTACH_FAILED,
        DETACH_FAILED,
        NOT_ATTACHED
      };
 
      class JNIThreadException {
      public:
 
        JNIThreadException(ExceptionType type) {
          this->type = type;
 
          switch (type) {
            case ATTACH_FAILED:
            {
              UG_LOG("UG-VRL: Attaching thread failed in "
                  << EMPHASIZE_BEGIN
                  << PRETTY_FUNCTION
                  << EMPHASIZE_END
                  << " in line: " << __LINE__ << " !");
            }
              break;
            case DETACH_FAILED:
            {
              UG_LOG("UG-VRL: Detaching thread failed in "
                  << EMPHASIZE_BEGIN
                  << PRETTY_FUNCTION
                  << EMPHASIZE_END
                  << " in line: " << __LINE__ << " !");
            }
              break;
            case NOT_ATTACHED:
            {
              UG_LOG("UG-VRL: Thread not attached in "
                  << EMPHASIZE_BEGIN
                  << PRETTY_FUNCTION
                  << EMPHASIZE_END
                  << " in line: " << __LINE__ << " !");
            }
              break;
          }
        }
 
        ExceptionType type;
      };
 
      inline JNIEnv* attachThread(JavaVM* javaVM) {
 
        // The following code raised a warning in newer GCC versions:
        // "dereferencing type-punned pointer will break strict-aliasing rules"
        // That is why we do it differently now, although this code
        // is officially used:
        //        JNIEnv* localEnv = NULL;
        //
        //        int result = javaVM->AttachCurrentThread(
        //            (void **) (&localEnv), NULL);
 
        JNIEnv** localEnvPtrPtr;
        JNIEnv* localEnv = NULL;
        localEnvPtrPtr = &localEnv;
 
        int result = javaVM->AttachCurrentThread(
            (void **) (localEnvPtrPtr), NULL);
 
        if (result < 0) {
          throw JNIThreadException(ATTACH_FAILED);
        }
 
        return localEnv;
      }
 
      inline void detachThread(JavaVM* javaVM) {
 
        int result = javaVM->DetachCurrentThread();
 
        if (result < 0) {
          throw JNIThreadException(DETACH_FAILED);
        }
      }
 
      inline JNIEnv* getEnv(JavaVM* javaVM) {
 
        // The following code raised a warning in newer GCC versions:
        // "dereferencing type-punned pointer will break strict-aliasing rules"
        // That is why we do it differently now, although this code
        // is officially used:
        //        JNIEnv* localEnv = NULL;
        //
        //        jint result = javaVM->GetEnv(
        //            (void **) (&localEnv), JNI_VERSION_1_2);
 
        JNIEnv** localEnvPtrPtr;
        JNIEnv* localEnv = NULL;
        localEnvPtrPtr = &localEnv;
 
        jint result = javaVM->GetEnv(
            (void **) (localEnvPtrPtr), JNI_VERSION_1_2);
 
        if (result != JNI_OK) {
          throw JNIThreadException(NOT_ATTACHED);
        }
 
        return localEnv;
      }
    } // threading::
  } // vrl::
} // ug::
 
#endif  /* THREADING_H */